Saladin odd stuff

[Douglas Greville]

2) On the under side of the turret roof directly behind the
gunner is a stowage device. It is thought this may be for
a ruptured case/stuck case extracter for the 76mm gun. (The
stowage diagram in the manual shows a rectangular object
in this stowage, but does not identify it. Noteworthy is
that it has been drawn 180° incorrect in direction
compared to all known surviving Saladins).

What goes here?

See attached pic "Odd mount behind gunner-1 red".

Regards
Doug